|
|
Vesicular trafficking from acidic compartments to the endoplasmic reticulum
Polidarová, Markéta ; Forstová, Jitka (advisor) ; Plocek, Vítězslav (referee)
The cell uses retrograde transport from endosomes to Golgi apparatus and further to the endoplasmic reticulum to recycle its receptors and other proteins. There are several pathways starting on different types of endosomes aimed to the trans-Golgi network and from it further to the endoplasmic reticulum. From the early and maturing endosomes the proteins are transported using the retromer complex. Rab9 GTPase is essential for transport from the late endosomes. Rab6 and Rab11 play major role in the transport form the recycling endosomes. There are two pathways going through the Golgi apparatus. The first one is mediated by COPI vesicles which are regulated by Arf1 GTPase and the pathway is sensitive to brefeldin A. The second pathway is regulated by Rab6 GTPase. Except for endogenous proteins the retrograde transport is used by protein toxins and small unenveloped DNA viruses as well. Rab6 pathway from the recycling endosomes and through the Golgi apparatus is characteristic for Shiga toxin. The retrograde transport of ricin starts on the early endosomes and is less clear. Scientists only started uncovering the transport of small unenveloped DNA viruses.
|
|
|
Rab-2A protein: its localization and function in human spermatozoa and fertilization
Sadílková, Lucie ; Postlerová, Pavla (advisor) ; Lánská, Eva (referee)
The Rab-2A protein belongs to the Rab family of monomeric G-proteins involved in the regulation of intracellular vesicular transport. Although several studies describing the role of Rab-2A protein in mammalian sperm have been published, the exact localization and function of this protein in male gametes have not been fully understood yet. In the diploma thesis, we were the first to describe the presence of Rab-2A in human sperm using 5C5, produced by the Laboratory of Reproductive Biology. Using the 5C5 antibody, we were able to identify several Rab-2A isoforms with molecular weights of 26, 24, 22, and 18 kDa in the human sperm lysate, confirmed by mass spectrometry analysis. Using the indirect immunofluorescence method, we localized Rab-2A in the acrosome area of both ejaculated and capacitated sperm. We noticed that Rab-2A leaves the sperm during the acrosomal exocytosis. We also found a reduced Rab-2A protein level in sperm of patients with various pathologies of ejaculate. Based on studies describing the role of Rab-2A in acrosome biogenesis and the presence of Rab-2A in bovine sperm perinuclear theca, we tried to detect Rab-2A in this protein layer in human sperm. However, the chosen method is apparently not applicable to human sperm and isolation has failed. Additionally, we demonstrated the...
|
|
|
The role of dynamin in human pathologies
Zavadilová, Kristýna ; Macůrková, Marie (advisor) ; Voleman, Luboš (referee)
Dynamin (DNM) belongs to the family of large GTPases, which are characterized by their ability to hydrolyse GTP. Although DNM participates in many cell processes such as synaptic recycling, Golgi transport or regulation of cytoskeletal dynamics, its most imporant function is membrane scission during vesicle budding from the plasma during clathrin-mediated endocytosis. Human DNM is encoded by three different genes. DNM1 and DNM3 are most expressed in the nervous system, particularly in the brain, whereas DNM2 is expressed ubiquitously. Mutations in this gene cause two congenital neuromuscular diseases. One of them is autosomal dominant type of Centronuclear myopathy, manifested by skeletal muscle atrophy, the other is dominant intermediate type of Charcot-Marie-Tooth neuropathy, which affects myelination and neurotransmission in the peripheral nervous system. Myopathy mutations may increase GTPase activity and higher DNM2 oligomerization, while neuropathy mutations may cause decreased GTPase activity and loss of phospholipid binding properties of DNM2. Despite these findings, the mechanism by which DNM2 cause these two diseases is still unknown. By understanding the function of DNM in cell processes can help in outlining therapeutic approaches for the aforementioned diseases.
|
|
|
Vesicular trafficking from acidic compartments to the endoplasmic reticulum
Polidarová, Markéta ; Forstová, Jitka (advisor) ; Plocek, Vítězslav (referee)
The cell uses retrograde transport from endosomes to Golgi apparatus and further to the endoplasmic reticulum to recycle its receptors and other proteins. There are several pathways starting on different types of endosomes aimed to the trans-Golgi network and from it further to the endoplasmic reticulum. From the early and maturing endosomes the proteins are transported using the retromer complex. Rab9 GTPase is essential for transport from the late endosomes. Rab6 and Rab11 play major role in the transport form the recycling endosomes. There are two pathways going through the Golgi apparatus. The first one is mediated by COPI vesicles which are regulated by Arf1 GTPase and the pathway is sensitive to brefeldin A. The second pathway is regulated by Rab6 GTPase. Except for endogenous proteins the retrograde transport is used by protein toxins and small unenveloped DNA viruses as well. Rab6 pathway from the recycling endosomes and through the Golgi apparatus is characteristic for Shiga toxin. The retrograde transport of ricin starts on the early endosomes and is less clear. Scientists only started uncovering the transport of small unenveloped DNA viruses.
|
guest ::
